1. Field of the Invention
The present invention relates, in general, to a machine for tamping a track composed of rails fastened to ties resting on ballast, the rails extending in a longitudinal direction and having a field side and a gauge side, respectively, and the ballast constituting tie supports located on said field side and gauge side.
2. Description of the Related Art
My earlier, commonly assigned U.S. Pat. No. 5,706,734 describes a machine of this type, having a tamping unit with which three or five adjacent ties of a track may be tamped. To that end, five tamping tine pairs are positioned on either side of the rail, with three vibration drives being associated with the tamping tine pairs. Due to the close succession of the tamping tine pairs, however, problems may arise with regard to the unhindered vertical adjustment of the tamping tine pairs or the squeezing motion of the tamping tines. The latter have to be squeezed partly in two opposite directions.
It has become known from U.S. Pat. No. 3,343,497 (German patent DE 15 34 022) to Stewart to arrange two tamping tine pairs one behind the other for tamping three successive ties of a track.